I don't get corporate mind sets. Why on earth would anyone want to refuse to install bug fixes?
It's not like an OS is more secure without Service Packs...

It's not a matter of refusing to install bug fixes - it's delaying installing those fixes until it can be confirmed that those fixes don't interfere with any critical applications.

For example, if SP1 breaks the software that runs a bank's call center, that's a business-breaker... bad publicity, and hundreds of people unable to work for as long as it takes to roll back the upgrade or fix the problem.